In general, a cartridge or blade unit of a safety razor has at least one blade with a cutting edge which is moved across the surface of the skin being shaved by means of a handle to which the cartridge is attached. Some shaving razors are provided with a spring biased cartridge that pivots relative to the handle to follow the contours of the skin during shaving. The cartridge may be mounted detachably on the handle to enable the cartridge to be replaced by a fresh cartridge when the blade sharpness has diminished to an unsatisfactory level, or it may be attached permanently to the handle with the intention that the entire razor be discarded when the blade or blades have become dulled. Razor cartridges usually include a guard which contacts the skin in front of the blade(s) and a cap for contacting the skin behind the blade(s) during shaving. The cap and guard may aid in establishing the so-called “shaving geometry”, i.e., the parameters which determine the blade orientation and position relative to the skin during shaving, which in turn have a strong influence on the shaving performance and efficacy of the razor. The cap may comprise a water leachable shaving aid to reduce drag and improve comfort. The guard may be generally rigid, for example formed integrally with a frame or platform structure which provides a support for the blades. Guards may also comprise softer elastomeric materials to improve skin stretching.
Wet shaving razors have evolved over the years to include a multiplicity of blades with the goal of increasing the closeness of a shave that is achieved while also providing a comfortable shaving experience. Increasing the number of blades on a shaving razor generally tends to increase the shaving efficiency of the razor and provide better distribution of compressive forces on the skin but can reduce the ability to trim, e.g., sideburns or near the nose. In order to improve the ability to trim an extra blade mounted on the rear of the razor cartridge has been provided to improve the ability to trim. Despite many marketing efforts, the typical consumer does not realize that an extra blade is even provided for trimming. Razor cartridges having a pivot locking mechanism have also been provided to trim mustache or sideburns or to shave around the nose. However, these devices have also not been obvious or intuitive to use for the consumer. Furthermore, these mechanisms are limited because they lock the cartridge pivot by locking the cartridge biasing member and/or they take the user's hand out of it's natural position in order to lock the pivot for trimming.
Thus, there is a need for a safety shaving razor having a pivot locking mechanism that is obvious and intuitive for a consumer to notice and utilize. What is also needed is a pivot locking mechanism for a shaving razor that functions independently of a cartridge biasing member.